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Kobalt SM2505LW Sliding Miter Saw Alignment Problem

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Forum topic by onestop posted 04-03-2015 11:56 AM 5312 views 0 times favorited 11 replies Add to Favorites Watch
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onestop

6 posts in 1357 days


04-03-2015 11:56 AM

Topic tags/keywords: miter saw question

So i bought this saw for better or worse to do some framing work. Worked just fine for chopping up 2×4s with virtually no setup. Lately I’ve been getting into some furniture work and i’ve discovered my saw is way off on my cuts on anything deeper than say 2-3”.

I followed the advice for tuning up my saw here: http://www.thisiscarpentry.com/2010/07/23/miter-saw-tune-up/

After doing the two-cut method I’ve found my cut closest to the fence is .58 but when i walk the blade out to the end of the cut on a 12” inch piece, the end cut is .789. This is massive.

I’ve checked the fence for true with my framing square, a level, etc… The table is flat, the fence is 90 to the blade.

The blade is practically new, Been used maybe 20 times since I bought it. When I lower the blade and just walk it across the cut front to back and vice versa, I can see it drift from the cutline…by quite a bit.

I think I’ve ruled out the fence being warped or out of alignment, the drift is so much I can’t imagine it’s deflection. And I’ve slowed down the speed of my cuts to the point of scorching the wood on my test cuts.

Thoughts?


11 replies so far

View Mark Davisson's profile

Mark Davisson

597 posts in 3521 days


#1 posted 04-03-2015 12:29 PM

I feel for you, man. I hope others with Kobalt experience come along with good feedback.

I would only suggest that you try to determine if forces caused by a running motor might be causing the problem. You’d do that by rolling (motor off) the blade along the surface of a work piece, allowing the blade to make slight dimples in the wood as it rolls. Then engage the motor and make the same cut. If the cut line tracks the “dimple line,” then the drift is not being caused by the running motor.

-- I'm selfless because it feels so good!

View JayT's profile

JayT

5961 posts in 2415 days


#2 posted 04-03-2015 12:46 PM

I have the same saw, but only really use it for construction projects, not much for furniture/woodworking. That said, it has stayed in alignment very well since I set it up and miters on baseboard, casing and crown come out pretty accurate.

Try doing three cuts of the two cut method, not just one. Is the amount off consistent? If yes, then your fence needs realigned. Doesn’t matter what the framing square says (it could be off, as well). The framing square will get you close, but only the actual cuts will tell you the whole story. If the cut isn’t square, it needs adjusted.

If the amount off varies, it’s probably in the sliding mechanism. Most sliding miter saws, including the Kobalt, use a twin tube sliding mechanism and all have some play, just that the better quality saws generally have less. You might check the bushings that the tubes slide through. Also, make sure that when you are doing sliding cuts, you put pressure in the same direction every time in order to reduce the effect of the play.

The Kobalt will never be the same quality and accuracy as a Kapex or even a Bosch, DeWalt or Hitachi, but should be a pretty good saw when set up right.

Good luck.

-- In matters of style, swim with the current; in matters of principle, stand like a rock. Thomas Jefferson

View dhazelton's profile

dhazelton

2794 posts in 2501 days


#3 posted 04-03-2015 01:11 PM

Was it doing that before the blade change? Have you switched to another blade to rule that out?

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onestop

6 posts in 1357 days


#4 posted 04-03-2015 01:23 PM

OK to answer a couple of questions so far. I changed the blade once from a 120 tooth that I was using to make some fine cuts but got burned up by my contractor when he borrowed the saw and started chopping up 4×4s. So i switched it out to a 60 tooth that’s been used maybe 6 times since.

That being said, I pulled the blade down and used three different squares, even bought the framing square new just to make sure. All three squares agreed the blade is 90 to the fence.

I did indeed do the tracking thing with the teeth pressed down on the blade, Rolled it lightly across my 12” piece just to make the indents for visual. I can watch it wander off the cutline about midway through. When I actually power the saw on and make the cut from front to back it lines up perfectly with my cutline in the front and then wanders off the cutline towards the back by as much as .105.

Interestingly enough when I cut two 1 bys or 2” pieces at 90 and flip them to match end to end…no gap. When I do the same thing at a 45 and flip to line them up…no gap.

It’s only when doing wide cuts front to back or even back to front (as a test) the saw just starts walking the dog and the difference become very noticeable.

EDIT: to add to this I also checked the fence with two different carpenters levels and there appears to be no warp in the fence. I also made sure to clamp my workpiece to the table to make sure it wasn’t accidentally bowing or moving while making the cuts.

This saw is about 1 year old and has been used approximately 10 times to make 20-30 cuts in total thus far.

View Alexedwards's profile

Alexedwards

2 posts in 8 days


#5 posted 12-08-2018 10:19 PM

I am having the same issues… I swapped out the blade that came with the saw, with a nicer diablo blade. My initial thoughts were something went wrong with the blade installation, however after 3+ hours of messing with the blade, and fence. I found that none of that was the problem. At least in my case, the rails of the saw are actually not true to the rest of the saw. So it makes sense that when the saw is being used like a chop saw, the cuts are fine, and when you use the full extension of the sliding aspect of the saw, the cuts are off “away from the fence”.

To test this yourself, get a large L-Shaped square, and set your fence square to the blade as if you’re making a chop cut. Then with the square in place, slide your saw out. Now not only will there by 1/16 to 1/8 of an inch gap between the square and the blade, but the blade will also no longer be square. to the L-Shaped square.

I, like yourself, have only had the saw for a year, so I plan on taking it back and not buying another one. Unless I can find someone else online with the same issues as us, that’s if you still have yours from 3 years ago.

View squazo's profile

squazo

111 posts in 1849 days


#6 posted 12-09-2018 12:33 AM

you mean its cutting more than 3/4 of an inch out of square? seems like you could just look at it and see what’s wrong. got any pictures?

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Alexedwards

2 posts in 8 days


#7 posted 12-09-2018 04:10 AM

Fully extended there is a 1/16 of an inch gap between the end of the square and the blade. When the blade is setup like a chop saw, the blade is square and touching the square. It’s not the fence, something is going on with the rails. I could send photos tomorrow.

View onestop's profile

onestop

6 posts in 1357 days


#8 posted 12-12-2018 10:28 AM

Just an update: sold the Kobalt piece of junk on craigslist. Bought the Dewalt 12 inch instead.

https://www.lowes.com/pd/DEWALT-12-in-15-Amp-Dual-Bevel-Sliding-Compound-Miter-Saw/3441818

The difference is night and day.

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ChefHDAN

1193 posts in 3054 days


#9 posted 12-12-2018 02:05 PM



Just an update: sold the Kobalt piece of junk on craigslist. Bought the Dewalt 12 inch instead.

The difference is night and day.
- onestop

Sucks to have to go through that and put money into a tool that can’t do the job no matter what. FWIW if you’re getting into building furniture, strongly suggest you get a sled built for your table saw for cross cut’s etc. There are lots of them in the Projects Section of LJ I only use the CMS for rough cuts or “less-Fine” types of joints. The sled makes it much simpler to be very accurate.

-- I've decided 1 mistake is really 2 opportunities to learn.. learn how to fix it... and learn how to not repeat it

View onestop's profile

onestop

6 posts in 1357 days


#10 posted 12-12-2018 04:11 PM

I have an enormous cross cut sled but honestly I rarely use it as I’ve found that I can be far more accurate and quicker setup with my Incra 3000SE.

View ChefHDAN's profile

ChefHDAN

1193 posts in 3054 days


#11 posted 12-12-2018 04:25 PM



I have an enormous cross cut sled but honestly I rarely use it as I ve found that I can be far more accurate and quicker setup with my Incra 3000SE.
- onestop

Ah, INCRA Trumps sled!

-- I've decided 1 mistake is really 2 opportunities to learn.. learn how to fix it... and learn how to not repeat it

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